The current application relates to an anchor having an expanding sleeve arranged around a threaded shank engaged in a plug for expanding the sleeve, the sleeve having an axially compressible, or collapsible, portion.
Such anchors are known, particularly from documents WO 96/25601, WO 92/04547 and DE 3023411.
When there is a desire to attach a part to a support, for example a masonry support, use can be made of such expansion anchors which are fixed in anchoring holes bored in the support. It can happen that the part that is to be fixed sits away from the support at some point. By using a sleeve-type anchor Comprising a compressible portion, it often becomes possible, when anchoring the anchor, to succeed in pressing the part against the support thanks to the compression of the compressible sleeve portion. However, the axial shortening of the compressible sleeve portion is sometimes not enough to press the part against the support before the anchor becomes perfectly anchored in its anchoring hole.
To this end, the current application relates to an expansion anchor of the type defined hereinabove, characterized in that the compressible sleeve portion comprises means that can be sheared and which are arranged so that after they have been sheared they allow the sleeve to be shortened axially.
Thus, under the action of the force exerted axially by the plug on the sleeve, as it expands, the shearing of the sleeve and its shortening in shear, on the one hand, and its compression and shortening in compression, on the other hand, are beneficially complete so as to ensure an overall axial shortening that is sufficient to press the part that is to be fixed against the support before the anchor becomes anchored.
As a preference, the means that can be sheared are designed to be sheared before the compressible means are compressed.
Advantageously, the means that can be sheared comprise bridges that can be sheared and that connect two sleeve portions that are designed to nest together axially, each bridge preferably being inclined to an axial plane.
As a preference also, the nesting sleeve portions are compressible.
In the preferred embodiment of the anchor of the invention, the sleeve consists of a cutout sheet-metal blank rolled up on itself.